The Hubble Space Telescope

Unlocking the Secrets of the Universe

Flight Operations Summary

Significant Spacecraft Anomalies: (The following are preliminary reports
of potential non-nominal performance that will be investigated.)
HSTARs:
13352 - SCI: GSAcq (1,2,1) results in Fine Lock Back-up (1,0,1)@150/0441z
COMPLETED OPS REQUEST:
19250-0 - Clear COS Event Flag 3 for prop 12810 visits 12-13@151/1813z
COMPLETED OPS NOTES:
none
FGS ACQ STATUS:
SCHEDULED SUCCESSFUL
FGS GSAcq 10 10
FGS REAcq 6 6
OBAD with Maneuver 5 4
SIGNIFICANT EVENTS:
The COS FUV Special Recovery activities (proposal 12810 visits 10 - 11) successfully completed
today without incident. The FUV was ramped to the 2nd HV plateau (-5010V/-4963V (160/157)) with
the QE grid off, no elevated counts or HV current transients were observed in the engineering
telemetry during or after the ramp. The STScI and MOSES2 Engineering Teams have examined the
relevant telemetry and confirmed all voltages, currents and temperatures were as expected. The
voltage and current monitors matched the signatures seen in SMOV. The COS Science Team at STScI
has examined the science data and DCE memory dumps and everything is nominal. No HV current
transients or unexpected elevated count rates were observed in the DCE memory dumps. The science
data consisted of 2 sets of dark and wavecal exposures. The exposures were collected immediately
after ramping to HVNom (160/157) and an hour later at the same HV level. Comparisons with SMOV
data taken with the QE grid on indicates comparable behavior with the grid off when the aging of
the detector and temporal fluctuations are considered. The Engineering and Science Teams have
given a "Go" to proceed with visit 12 and 13. Visits 12 and 13 are scheduled for Thursday May 31th
(DOY 152). The COS event flag 3 was cleared @151/18:14 via OR 19250 -jb